This application claims the priority of German application No. 197 56 976.5, filed Dec. 20, 1997, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a brake device for vehicles, in which wheel brake actuators (wheel brake units) are provided with electronic circuits by at least one communications system.
A brake and steering system for a vehicle in which the wheel brakes and the steering system of the vehicle can be actuated by a communications system is disclosed, for example, in DE 195 26 250 A1. In order to avoid a continuous mechanical connection between the steering wheel which can be activated by the driver and the steered wheels and in order to avoid a continuous mechanical and/or hydraulic connection between the brake pedal which can be activated by the driver and the service brake for the wheels, a fault-tolerant, preferably redundant arithmetic unit determines a desired braking effect at least for each wheel. A desired steering effect is determined for each wheel with a steering function, on the basis of sensor signals. The braking function and the steering function for the wheels are closed-loop and/or open-loop controlled by setpoint value systems on the basis of the desired braking effect and desired steering effect which are determined.
A redundant communications system, for example, a databus which is of a redundant design, is used to transmit the data.
A problem with such a brake and steering system is that in order to construct a fault tolerance system a large number of data has to be transmitted simultaneously. In particular, a large number of additional data management messages has to be transported via the communications system.